Hitachi 7K400 Specifications - Page 122
DMA queued commands
![]() |
UPC - 000053412935
View all Hitachi 7K400 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 122 highlights
11.5 DMA queued commands DMA queued commands are • Read DMA Queued • Read DMA Queued Ext • Service • Write DMA Queued • Write DMA Queued Ext 1. Command Issue a. the host writes any required parameters to the Features, Sector Count, Sector Number, Cylinder, and Device/Head registers. b. the host writes command code to the Command Register. c. the device sets BSY. d. the device clears or sets REL. e. the device clears BDY. 2. Data Transfer and Command Completion. If the device is ready for data transfer (REL is cleared), a. the host transfers the data for the command identified by the Tag number using tghe DMA transfer protocol currently in effect. b. the device generates an interrupt to the host when all of the data has been transferred. c. the host may issue another command or wait for service request from the device. 3. Bus release. If the device is not ready for data transfer (REL is sent), a. the device generates an interrupt if release interrupt is enabled. b. the host may issue another command or wait for service request from the device. Deskstar 7K400 Hard Disk Drive Specification 108
![](/manual_guide/products/hitachi-7k400-specifications-548f643/122.png)